Control for radio apparatus



Nov. 3, 1936. G. M. ROSENBLUM 2,059,279

I CONTROL FOR RADIO APARATUS Filed May 29, 1929 4 sheets-sheet 1 NOV. 3,1.936. G, M ROSENBLUM 2,059,279

CONTROL FOR RADIO APPARATUS Filed' May 29, 1929 4 sheets-sheet 2 m un nu1m 1||| nu un nu nu un INVENTOR my mxm AT oR'NEY G. M. ROSENBLUM CONTROLFOR RADIO APPARATUS Nov. 3, 1936.

4 SheetS-Sheet 3 Filed May 29, 1929 @ru 12v M2M A TOFNEY w" qw a INVETORNOV. 3, 1936. G, M, ROSENBLUM 2,059,279

CONTROL FOR RADIO APPARATUS Filed AMay 29, 1929 4 Sheets-Sheet 4 lNvE'TOR f mbwwv M2M Afr oR'Ni-:Y

'Patented Nov. 3,- K193.6

UNITED STATES PATENT OFFICE coN'raoL Foa aAmo APPARATUS Application May29, 1929, Serial No. 366,882

4 Claims.

'I'his invention relates to the control of radio apparatus, particularlyradio receiving sets.

, Special objects of the invention are to provide reliable and practicalremote control by which a radio receiving set or the like may be turnedon and oli and different stations be selected at will;

to provide at the Aremote control stationv means Y for indicating theselecting operation and for showing to the operator the conditions atthe receiving set; to provide in conjunction with the remote control orindependently of the same, an

outlet or a remote speaker or head set by which the operator may checkthe operation of the set, or use an additional speaker at a pointdistant from the set; to provide in conjunction with the above orindependently of the same a program determining and selecting device bywhich the receiving set may be automatically turned on or oil? atdifferent times and by which different stations can be automatically cutin for selected periods.

Further objects are to accomplish the above in a commercially practicalway without resorting to undue complications and to provide arbitrarycontrols by which the action of the automatic controls may be supersededat will, permitting the radio apparatus then to be handled in the usualor ordinary ways.

The foregoing and other desirable objects are attained in this inventionby certain novel features of construction, combination and relations ofparts, as set Vforth in the following specication and broadly covered inthe claims.

The drawings accompanying and' forming part oi' the specification,illustrate an embodiment of the invention, but as this illustration isprimarily for purposes of disclosure, it should be understood that thestructure may be modied in various ways without departure from the truespirit and broad scope of the invention.

Fig. 1 is a broken front 'view illustrating the apparatus as built intoor incorporated with a radio receiving set; Fig. 2 is a broken side viewof the clock Contact mechanism with the panel and other portionsappearing in section; Fig. 3 is a front and part sectional view of theclock contact mechanism as on the .plane of line 3-3 of Fig. 2; Fig. 4is a broken part sectional view showing the motor driven selectormechanism coupled 501, thencontrol shaft of the receiving 4set;

Je. ,b s. l f, hetwiringz otoneeiot fthesaA 55 is a' diagrammatic viewillu e wirmg 0f (Cl. Z-20) the selector switch mechanism, timingswitchesf etc., the wiring in this view being a continuation of thatshown in Fig. 6.

The invention is adapted for use with radio yreceiving sets generallyand therefore the receiving set indicated at 9 in Fig. 1 may beconsidered of any conventional or special design. This particular set isshown as having a dial or tuning control I0 by which the set may be arbitrarily tuned to select different stationsy and a suitable volumecontrol II.

The selection of certain stations may be automatically effected in theconstructionA shown by the station selecting push button switches shownat I2, I3, I4, I5, I6, located on the front of the panel with stationindicating signal lamps I2', I3', I4', I5', I5' above the same. Theparticular set shown is turned on by push button switch I1 and can beturned 01T by push button `switch I8. At one side of these on and orfbuttons, there is indicated a so-called emergency switch button I9, thepurpose of which will be described later and at one side of the latter,there is indicated a toggle switch 20 for cutting the timing clock intoand out of operation.'

The timing clock is illustrated at 2| mounted in the face mount in thepanel of the receiving set. Below the clock on the face of the panel arethe station selecting time switches 22, these being indicated, one foreach half hour period of 12 h ours, or otherwise stated, one switch foreach half hour of a full 12 hours. 'Ihe time at which each of theseswitches becomes effective may be indicated on the panel under theswitch as shown and the stationswhich these switches control may beindicatedon a scale at each switch vas shown. In this particularillustration, ve stations, which for example, may be designated A, B, C,D, E, are controlled by each switch, these being the same five stationscontrolled by the arbitrary selecting push buttons I2, I3, I4, I5, I6.

At each half hour period, the clock 2I automatically cuts in one of thestation selecting time switches 22, rendering that particular switchthen effective to cut in the station to which it has been turned.'I'hese station selecting time switches are indicated as" having off andon positions at the ends ofthe station scales, so that instead ofselecting a station, they may serve siinply to out the receiving set offor to continue it in operation at the station last selected.

lThe niannerzinl wh-iclsrthe station selecting time switchesaneconnectedin,circuitbythe:clock will .pibe understood zfromEi'gs.: 2,3,2 and's'lziwhich indicate the hour hand arbor 23 of the clock ascarrying a switch arm 24 contacting at each half hour with one of theswitch buttons 25 connected by wiring 2li` with the contact arms 21 ofthe respective station selecting time switches 22, (Fig. 7).

The remote control stations indicated in connection with the receivingapparatus in Fig. l and shown separately in Figs. 5 and 6, consist eachof a suitable panel 28 connected by a cable 29 with the receiving set,said cable usually terminating in amultiple prong plug 3U, enabling allthe circuits of the remote control station tobe plugged in at once intothe receiving set.

As shown in the detailed view Fig. 5, each remote control panel carriesa set of station selecting push buttons I2a, I3a, I4a, I5a, Ilia, a setof signal lights for the same designated I2", I3", I4, I5", I6, radiostarting and stopping switches I1a and |80, and an emergency push buttonI9a and a clock on and oil switch 20a.. These controls and indicatorsare shown arranged in three rows similar to the equivalent controls andindicators on the panel of the radio set.

In addition to the control functions, the remote control panel isutilized as a station extension in the present disclosure by providingit with phone tip jacks 3|, to receive the contact pins of a speaker orhead set cord. This isa special advantage when the remote controlstation is located a considerable distance from the radio set, enablingthe operator to check the operation of the radio set at all times. v

The automatic adjustment of the radio set is effected in the presentdisclosure by an electric motor shown at 32 in Figs. l, 4, and 7,driving through the reduction gearing, including worm gearing 33 andchain and sprocket gearing 34, a control shaft 35 in line with andcoupled up to the tuning condenser shaft 36 by a friction clutchcomprising conical clutch elements 31, 38 on the two shafts. The tuningcondensers are indicated at 39 all mounted on the same shaft, but itshould be understood that these may be separate condensers or be otherforms of tuning devices, depending on the type of radio set.

The clutch element 31 is shown as slidingly keyed on the control shaftat 40 and as pressed toward the companion clutch member 38 by spring 4I.This construction provides a slip coupling which will yield and preventinjury to any of the partsand which furthermore, will enable independentcontrol of the radio set through the medium of the tuning dial III orother customary control. In order that the control shaft Aand condensershaft' may be turned to a predetermined relation, after the set has beenindependently operated by means of the tuning dial, the clutch element38 isshown as having a spring pressed ball 42 seated in the face of thesame for cooperation with a vent 43 inthe face of the companion clutchmember 31, the 'same providing a feeler by which the operator may knowwhen the dial has been turned far enough to bring the two shaft sectionsinto proper registry. The control mechanism for the motor comprises inthe present illustration of a. set of motor circuit relays 44, 45, 46,41, 48, Fig. 7, one for each of the stations A, B, C, D. etc. which theapparatus is to select, having armaturecontacts 44', 45', 43', 41', 48',connected by wiring 44", 45", 4B", 41", 48", with brushes 41. 45a, 45d.41a, 43a, Figs. 4 and '1, engaging a contact plate or the segments of acontact plate 5I mounted on the insulated support 5I on the controlshaft 35 (Fig. 4) and having a radially extending insulating break 52(Fig. 7) which will interrupt the motor circuit when it reaches thebrush of the relay which has been energized.

The energy for operating the motor, control relays and indicator lightsmay be taken from the ordinary house lighting circuit. This isaccomplished in the present disclosure by using a 110 volt universalmotor connected across the line and "step-down transformers 53, 54, 55,Fig. 'l having their primaries on the 110 volt A. C. circuit and theirsecondaries connected to iced the relays and lamps.

The two sides of the 110 volt line are designated 56, 51, in Fig. 7 andthe line 53 is shown running through a normally closed emergency switchI9 and then continuing as such in Fig. 6 up through another normallyclosed emergency switch I9a on the remote control panel. One side of themotor is shown connected by a branch 51 with the service wire 51 and theother side of the motor is connected by wiring 58 to the control plateor plate segments 50, from which, return to the other side of the lineis eiected by one of the brushes 44a, 45a, etc., wiring 44, etc., relaycontacts 44' em., and relay armatures 44h, 45h, 4Gb, 41h, 48h and wiring59, through the closed emergency push button IBa, Fig. 6 to the oppositeline 56.

The primaries of the transformers 53 and l5 are shown connected inparallel with the motor by Wiring 51, 60, 6I, and 58, Fig. 7, so as toreceive energy from the line when the motor is in operation. Thesecondaries in these two transformers 53, 55, furnish energy torectifiers 62, 63, the first lof these supplying energy for the selectorrelays 44 and indicator lights I2', I3', etc. through wiring; one sideof which is designated 64a-34 and contains the push button selectorswitches I2, I3, I4, I5, I6 and the other side of which is designated65. The indicator lights I2', I3', etc. are shown connected in on thesesame lines 84, l5

- by suitable branch wiring shown at 66.

The selector relays are shown as of the ,selilocking type, so as torender it unnecessary for the operator to hold the push button switchwhile the motor is effecting the selecting operation. I'I'he connectionsfor this purpose include the relatively stationary and movable armaturecontacts 81', 'E8 respectively, the armature movable contact beingconnected by branch wiring 63 with the feed line 64a of the rectifierand the stationary contact 61 being connected by the wiring 1I back intothe line 64 at the other side of the selector switches I2, I3, etc., thecurrent returningthrough the relay and the line 64a back to therectiiier. From this it will be seen that as `soon as one of the pushbuttons I2, I3 is operated to close a circuit through one of the relays44, 43, etc., said relay will close its own circuit inde pendently ofthe push buttons which initially close the circiut through the relay and`further that this circuit through the relay, will remain closed duringthe remainder of the period 0I operation oi the motor or until therotation of the commutator brings the gap or circuit interrupting breaktherein into register with the brush 44a, etc., of that particularrelay. Thus, it will be clear that when a selector push button isoperated, the relay for that particular button will be energized,closing the circuit through the motor and holding it closed until themotor has turned the contact disc far enough to bring the break intoregister for that relay. These brushes are angularly related or offsetto determine the movement necessary for bringing in a particular stationand hence the motor will stop after it` has turned the tuning InFig. 4,the selector brushes Ma,I etc., are shown as supported in angularlyadjustable relation by having hub portions 1| rotatably engaged in4insulated relation upon a common support 12. This support isillustrated as an insulating sleeve concentric with and surrounding thecontrol shaft, being carried by a bracket 13, so that it does not touchsaid shaft. This sleeve is shownA secured stationary in the bracket by aset screw 14. The hub portion 1| of the brushes may be held frictionallyon the insulating support or be secured in their adjustable relationsthereon by set screws or the like. 'The purpose of such adjustment, itwill be seen, is to enable the brushes to be independently set fordifferent desired stations.

The second rectifier 63, Fig. '7, is provided to energize a restoringrelay 15 through direct wiring 16. As transformers 53 and 55 are inparallel, both rectifiers 62 and 63 will come into operation at the sametime, the first rectifier fur- .'nishing current for the relaysandsignal lights yau wiring 80 with wiring 59of the other side of the iline. It will be apparent therefore, that when a push button is operatedto effect a station selecting' operation, the so-called restoring relay15 will be energized from transformer 55 and rec- A tie'r 63 toimmediately break the circuit through primary of transformer 54. Hence,while the motor is operating, the selected relay and signal out when themotor stops after having completed its station-selecting function.' Asthe primary circuit of primary transformer 55 is also broken in thissame circuit opening operation; the vrectifier 63 is deprived of'currentat this time, so that relay 15 then releases its armature 11, whichthereupon closes ,circuit at 18, 19 through primary of the secondtransformer 54. `The secondary of Y this transformer is in parallel withthe secondary" of transformer 53, whereby transformer 54 is inconditionto furnish current to rectifier 62 at the end of the station selectingoperation at which time transformers 53 and 55 are inactive.y

This automatically places rectifier 62m condition to furnish current forthe next selecting operation.

.The relay 15 is of the slow returning typeI or constructed so that whendeenergized,`it will Permit its armature to close the 54 transformerprimary circuit at 18 after the selecting relay which has just been Ioperated has opened the selector circuit. 1 f `Q The relay 15furthermore, in the present disclosure' is utilized to open the speakeror output circuit of the radio set during the station. select ingmovements by providing it with the extra,

relatively stationary and movable contacts 8|, 82, connected by wiring83 with one terminal 84 of the speaker output of the set and wiring 85in series with the speaker and the other, side 86 Aof thespeaker output.Hence, each time the station selection is being effected the speaker atthe set and the speakers, if any, at the remote control boards areautomatically cut oif to avoid undesirable sounds and are automaticallybrought into circuit action at the completion of the station selectingoperation.

The operation of the remote control panel will be understood from theforegoing, particularly when Fig. 6 showing the wiring oi!v this remotecontrol is placed above Fig. 7 with the terminals pf one wiring diagramin alignment with the terminals of the wiring in the other diagram, itbeing vthen seen that the station selector buttons I 2a, 3a, etc., onthe remote control panel are in parallel respectively with thecorresponding push buttons' l2, I3, etc., on the radio set. Also it willbe noted that the indicator lamps I2", I3", etc. are in parallel withthe indicator lamps I2', I3', etc., at the radio set, and so will showsimultaneously with those indicator lamps. The so-called onw switch |1afor starting the radio set from theremote control point is shownconnected by the wiring 81 with one side of 'the rectifier 88, suppliedwith current from the transformer 88', the return from this rectifierbeing indicated 89 and shown as extending through an onf relay 98, Fig.7. Connected across the lines 81, 89, Fig. '1 in parallel withthe'remote starting switch |1a, Fig. 6,'. is the starting or on switchI1, which is located at the radio set. The effect therefore of operatingeither push'button I1 or |1a is to close an energizing circuit throughrelay 90, which thereupon draws its armature 9| into engagement withstationary contact 92 to close its own energizing circuit independentlyofthe push buttons by way of conductor 93, through the normally closedoff switch |8a, Fig. 6 and conductor 94 through the normally closed offswitch I8 at the radio set, Fig. '1, and wiring 95, 89, relay torectifier 88, the opposite side'of this rectifier being connected witharmature lever 9| by "on circuit, there is shown an armature lever 2,Fig. 7 vfor engagement with a contact I|3 in lthe wiring 96, saidarmature being under control of a relay IIIl.

4o the wiring 81, 96. Interposed in this so-called The on or circuitclosing relay 98 also con- /trols the relatively movable and stationarycon-A Jset or at a remote point serves to close the energizing circuitof the radio receiving set.

The operation of the station selecting time 'switches 22 willI beunderstood from Fig. 1, in whichV two of these switches, those for the6:30 and '1 oclock time periods are shown connected with the appropriatecontact ybuttons 25 on the main clock timing switch. In this particularinstance, the contact arm 21 of the '6:30 time switch is shown turned toB station and the c'ontact arm of the '1 oclock timing switch is shownturned'to the ofl' point. As a result, at 6:30 station B will be broughtin and at the half hour period ending at '1, the set will be cut off.This follows because of the fact that when the clock IUI, |02, |83, 18,64 to the B station relay 45 and` by the return Wiring 65, to one sideof rectifier 62, the other side of said rectifier being connected 75 bythe wiring 64a and the extension wiring |04 to the main clock switch 20,which isconnected with the movable arm 24 of the clock switch by wiring|05.

The supplemental clock switch 20a on the remote station panel, Fig. 6,is connected in paral' lel with this main clock switch 20 on the radioset by the wiring |05, |06, Figs. 1 and 6 and return wiring |01, .|08,so that when the clock switch at the radio set is left open, the remotecontrol clock switch 20a may be used to turn the clock control or timingmechanism on or ofi atvwill. When in the example supposed, Fig. 7, thehalf hour contact arm 24 reaches the next contact button 25 at 7 oclock,current is conducted iroin that button through connection 2B to leverarm 21 of the 7 oclock time switch and as this stands on the "05button,4 such current continues by conductor |05 to an off relay IIIland connections III, B5 to rectifier 62 'and'from this rectifier bywiring 64a, |04, switch 20 or 20a to the clock contact arm. This offrelay when so energized lifts its armature |I2 from contact |I3breakingthe circuitat this point and -thus opening the circuit from rectifier88, which energized the holding relay 90. The circuit of this holdingrelay as previously described, is from Vrectifier 00, continuing throughwiring 89, 95,

`through the normally closed off switch I8 and wiring 94 through theremote control normally closed off switch |8a, Fig. 6, wiring 93,contact 92, lever 9|, wiring 95 to the opposite side of the rectifier,the latter portion of this wiring including the contact I3 and thearmature H2, which latter has been lifted by energization of relay I] tobreak the circuit. The off relay I I0 thus ex ercises a direct controlover the relay 80, which normally holds down the armature 91 forclosingl the circuit through the primary of transformer |00, the latterfurnishing the current for the tubes of the set. Consequently, when oneof the timing switches is turned to off, the set will be automaticallyshut off when the clock con tact arm reaches the time of that particulartiming switch. Thus by setting these different time switches at oir, theradio set will be automatM ically shut oil? when that time is reached.

The so-called holding relay 90, the armature of which is open when theset is not in operation is shown in Fig. 7 with its armature in a closedposition, this merely being so for the purpose of more clearlyexplaining the action oi' relay I0. If desired, the radio set may beautomatically turned on at any desired time by turning the timev switchfor that period to the on position. These on contacts are shown in Fig.7 connected by wiring |I4 with one side of the on relay H5,l

the other side of such relay being connected by wiring IIS, III, 65 withrectifier 62, the return .from such`rectifier being by wiring 64a, |04,

through either clock 'switch 20 and wiring |05 to the clock contact arm24 or through switch 28, Fig. 6, by way of wiring |08, |01, |06, |05, tothe switch contact arm 24.

When on switch ||5 is thus energized, it

. 80 and fromthis rectifier by wiring 01,96 to the armature |I1a.Consequently, operation of the on" relay I|5 causs the-holding relay 90to be energized, closes the circuit through the set transformer |00.

It will be observed that the set may be turned on by either the onswitches I1, I1a. atthe s .et or remote control or.by the on contactsoi.'

the clock time system. The on switches I1 'and |1a are in parallel witheach other and in series with a holding relay 90, while the on contactsof the station selecting time switches are in series with the on relay|I5, which controls the' circuit through the holding relay 90 by itsarmature ||1a and its contact |I1.

The set may be turned off by operation of either the off switches I8 or|811 at the set or remote control panel. These switches being in serieswith each other and with the holding relay 90, so that opening of eitherswitch will break the circuit through said relay, a similar result iseffected by the oil contacts of the clock time system, which areconnected as described to energize the oi magnet |I0 for breaking thecircuit of the holding relay magnet.

The invention Vit will be seen provides many possibilities. When theclock system is used, the various time switches may be set to bring in anumber of selected radio programs, extending in the present disclosureover a period of 12 hours. The program may be terminated at apredetermined time by turning the switch for that particular time to theoff position. Thus, the radio set may be caused to bring in thedifferent selected stations for a desired period of time and then beautomatically turned off. The program instead of being continuous may beinterrupted, if desired, by setting the switch for the time which it isdesired to stop the reception at the off position and setting the switchfor the time, which it is desired to start reception again, at the "onposition. Then at the time of the iirst switch, the receiving set willbe automatically cut oil?, and after the desired interval of time, thereceiving set will be automatically turned on again.

At any time, the action of the automatic program arranging mechanism maybe arbitrarily interrupted and other stations be brought in or the setbe turned off by simply operating the se lector push buttons or the offswitch on the set itself, or at one of the remote control stations.After thus arbitrarily operating the set, the automatic time control maybe allowed to resume the automatic program selecting operation. If atany time it is desired to bring in other stations than those controlledby the push buttons or time switches, the set may be arbitrarily .tunedby means oi its tuning controls, the slip clutch in the motor drivepermitting this operation and the feeler mechanism of this clutchenabling the operator to turn the tuning dial back to a properregistration or alignment of the motor driven control shaft and thetuning controls of the set.

When making the station changes, the speaker is automatically cut oirand when tuning action.

is completed, the. speaker is again automatically cut into circuit.

The remote control enables a supervisory control or operation of thereceiving set at all times, the arbitrary selecting of different desiredstations and the shutting oi or turning on of the set at will. With thisremote control, also, the clock timing mechanism can be cut into or outof service. Also, if a remote speaker isdesired, the same can be pluggedinto the remote panel board or a. head set may be plugged into thispanel when for instance, it may be desired to test the quality orcharacter of the reception.

The use of multiple prong plugs and sockets l set. The motor, contactsegment, drive mechanism relays and push buttons are all relativelysimple devices and parts, and can be combined compactly in acomparatively small space, so that the same may be built into thereceiving set or form a small outside unit connected up with the tuningcontrol mechanism of the set. Similarly, the clock timing mechanism isof relatively simple construction and may be combined in the radio setas illustrated or made up as a separate unit, for example in combinationwith the remote control apparatus.

The purpose yof the so-called emergency switches I9 at the set and ISaat the remote control stations is to restore the actuating mechanism toa so-calledl normal or starting condition after an accidental orincorrect operation of the selector controls, such an accidental orincorrect operation might be the simultaneous actuation of two or moreof the selector push buttons.

' Should this happen, the indicator lights of all the buttons operatedwill show. This in itself at once notifies the operator of the incorrectactuation of the control buttons. Either one of the emergencyv switchesI9 or I9a, if then operated, will cut the motor feed circuit, at the setin Figs. 1 and 7 or at the remote control stations, Figs. 5 and 6 andthe breaking of this motor circuit immediately stops the motor,deenergizes the relays and puts out the `signal lights, leaving theapparatus in condition to initiate any desired station selectingoperation.

The emergency controls I9, I 9a, may be used to correct other conditionsin the apparatus, for example, such as might result from operating oneof the selector push buttons at a time when the station of thatparticular selector was being received. In such a case, the relay ofthat selector circuit would be energized and would hold its circuitclosed, indicating the fact by the lighting vof the signal lamp for thatstation. 'I'he motor circuit being incomplete at the break in thecontact disc would prevent the motor from starting. The signal light maythen be put out and the relay be de-energized, so as not to interferewith the next selector operation, by simply operating either the localemergency switch I9 at the set or the emergency control button at anyone of the remote control panels.

While the apparatus is shown operated-on alternating current, it will beobvious that the same may be operated on direct current, by making theconventional alterations known for' changing from alternating to directcurrent operation.

It will be evident that many changes and modications may be made in thestructure, all within the scope of the claims and in view of this fact,it should be understood that the terms employed herein are used in adescriptive rather than in a limiting. sense, except forV suchlimitations as may be required by the state of the art.

` What is claimed is:

1 In combination with radio apparatus, havdifferent stations, saidpre-setting devices comprising contact arms of different lengthsangularly adjustable about a common center and the motor stopping meansfurther including a motor driven commutator operating on said center andhaving contact rings in line with said arms and lwith circuitinterrupting gaps therein cooperable with said arms in differentpositions of adjustment of the latter.

2. In combination, a radio receiving set having -means for tuning thesame to receive different stations, motor means for operating saidtuning means for effecting the different station receiving adjustmentsof said radio set, station selecting switches for effecting differentstation receiving adjustment operations of said motor means, time switchmeans for rendering said station selecting switches operative at variousselected time periods, a speaker associated with said radio receivingset and means for automatically rendering said speaker inoperativethroughout the range of adjustment determined by a particular stationselecting switch at a time determined by said time switch means and forrendering the same operative only upon completion of the stationreceiving adjustment for such predetermined time period.

3. In apparatus of the character disclosed, an electric motor, means fortiming the operation of said motor through diierent ranges of movement,means for selecting the different ranges of movement of said timingmechanism, a power source for the motor and selecting means, the timemechanism including means for disconnecting said power source at the endof the selected timed motor operation, means for automaticallyreconnecting said power source at the end of such selected motoroperation in condition for subsequent timed operations of the motor,said power source and reconnecting means including three transformers, arectifier supplied' with energy from two of said transformers andconnected withthe `selector means, a rectifier supplied with energy fromthe third transformer and means operated from said second rectifier forcontrolling supply of energy from one of the Afirst two transformers tothe first rectifier.

.member having concentric annular conducting and non-conducting portionsand said brush member comprising radially spaced brushes in cooperativerelation with said concentric annular conducting andnon-conductingportions of the commutator, station selecting -switches each having anumber of different station contacts connectedwith different cooperatingelements of said commutator mechanism and whereby the stopping positionofthe tuning shaft when operated bythe motor will be determined by theangularly set position of one of the adjustable elements of thecommutator mechanism connected with a station contact of one of saidstation selecting switchesy and a time switch having contacts connectedwith different station selecting switches and vwhereby the respectivestation selecting switches will come into control only attimesdetermined by said time switch.

GEORGE M. ROSENBLUM. I

